The invention relates generally to turbine engines and more specifically to a method for automatically identifying and classifying defects in turbine engine blades.
Turbine engines essentially consist of an air compressor, a combustion chamber and a turbine. The compressors compress air which is mixed with fuel and channeled to the combustor. The compressed air mixed with fuel is ignited within the combustion chamber to generate combustion gases, which are then channeled to the turbine. Within the turbine, the hot combustion gases blow over the turbine blades. Cooling channels in the turbine engine blades receive cooler air from the compressor of the turbine engine and pass air through the blades. Holes in the leading and trailing edges of the blades form showerheads for exhausting cooling fluids from the internal passages to provide film cooling on the outer surfaces of the turbine blades. As will be appreciated by those skilled in the art, the size, shape and angle of the cooling holes determine the effectiveness of the cooling flow and can have an impact on the airflow pattern over the surface of the blades. However, during manufacturing, certain defects (for example, caused by poor laser drilling techniques or by the presence of residual core material) may be formed in these holes, leading to the formation of blocked cooling holes, leading to excessive or uneven heating and ultimately damaged turbine blades.
These defects may generally be identified through manual inspections of the X-ray images of the turbine blade after the application of image processing enhancement algorithms. Automated defect recognition techniques may also be used to identify defects in turbine blades. However, these techniques are typically based on statistical analysis and require huge reference databases to perform defect classification and identification. Moreover, these approaches involve significant training effort and set up time.
It would be desirable to develop an efficient technique for automatically identifying defects in turbine engine blades that improves throughput, reduces inspection cost and improves inspection quality.